Abstract

Background

Since we were able to isolate viable virus from brain and lung of H7N1 low pathogenic
avian influenza virus (LPAIV) infected chickens, we here examined the distribution
of different LPAIV strains in chickens by measuring the viral AI RNA load in multiple
organs. Subtypes of H5 (H5N1, H5N2), H7 (H7N1, H7N7) and H9 (H9N2), of chicken (H5N2,
H7N1, H7N7, H9N2), or mallard (H5N1) origin were tested. The actual presence of viable
virus was evaluated with virus isolation in organs of H7N7 inoculated chickens.

Findings

Viral RNA was found by PCR in lung, brain, intestine, peripheral blood mononuclear
cells, heart, liver, kidney and spleen from chickens infected with chicken isolated
LPAIV H5N2, H7N1, H7N7 or H9N2. H7N7 virus could be isolated from lung, ileum, heart,
liver, kidney and spleen, but not from brain, which was in agreement with the data
from the PCR. Infection with mallard isolated H5N1 LPAIV resulted in viral RNA detection
in lung and peripheral blood mononuclear cells only.

Conclusion

We speculate that chicken isolated LPAI viruses are spreading systemically in chicken,
independently of the strain.